1. Field of the Invention
The present invention concerns, an apparatus, such as a mail processing apparatus, of the type having a cavity in which a scale module can be plugged, the cavity being covered by a cover if the scale module is not being used.
2. Description of the Prior Art
A known franking machine Jetmail® by the manufacturer Francotyp Postalia Beteiligungs AG is commercially available for offices with average to high mailing needs and has a fixed, installed, static scale. A plate part establishes a ground connection with the chassis of the franking machine. The franking machine evaluates the weight measurement values and has a postage computer in order to ultimately print out a franking value on a mailpiece.
A franking machine for users with small mailing needs is also known to which an external postage scale can be attached via a cable. Inside a security housing, the franking machine T1000, also commercially available from Francotyp-Postalia Beteiligungs AG, has a fixed thermotransfer print head for printing a franking imprint and a standard interface for connection of the postage scale. If the scale fails due to an electrostatic discharge, the franking machine still can be operated with the franking value being manually entered. The franking machine has a metallic chassis for discharging electrostatic charges, and for reduction of interfering irradiation, and the interference resistance is further increased by an electrically-conductive protective coating applied internally on the security housing. Protection of both the scale and the franking machine, however, would require a relatively high expenditure. The RS232 interface between the franking machine and the external postage scale contains a driver and level converter for decoupling of both devices. Moreover, a connection cable is necessary for connection of the scale with the franking machine.
A weighing platform, model no. WP02/WP5, for weight measurement of a maximum mass of 2 kg, is known, which alternatively can be arranged next to or on the housing of an inkjet franking machine of the type Neopost IJ45, and can be connected via a cable (FACTS, das Testmagazin furs moderne Büro, issue 5, May 2003, 10th volume). The weighing platform has neither display nor keyboard and is thus is relatively inexpensive. The aforementioned disadvantages persist; moreover, the weighing platform is placed only loosely on the housing and thus is unattached thereto.
Inside a security housing, the known franking machine mymail® commercially available from Francotyp-Postalia Beteiligungs AG, the manufacturer has a movably-arranged inkjet print head for printing a franking imprint. The housing is formed of an upper housing part and lower housing part, the former being fashioned for attachment of an upgradeable (retro-fittable) weighing unit. According to German patent application DE 101 14 52 9, the first housing part has a cavity (indentation) that is fashioned for insertion of the weighing unit. An attachment arrangement for attachment of a cap that seals the cavity is provided in the region of the cavity. The cap is removed before the attachment of the upgradeable weighing unit for which the attachment arrangement is used. The attachment arrangement is fashioned pin-like and the upgradeable weighing unit has rubber feet with corresponding openings for insertion of the rubber feet on the pin-like attachment arrangement. Grounding of the weighing unit thus does not ensue via this attachment arrangement.
An electrical connection of the weighing unit with the franking machine mymail® ensues exclusively via a scale connection cable inside the housing. The interrogation of the digital weight value by the microprocessor proceed via an I2C bus. The mounting capability of the weighing unit is hampered by the necessity of providing contacting by plugging in a cable. Moreover, it is a disadvantage that the scale module exhibits both a relatively high irradiation and a relatively low interference resistance.
A scale module should possess substantial protection against damage due to electrostatic discharge (ESD) and with regard to electromagnetic interference (EMI).
In the prior art it is known to use thick, plaited ground cables for grounding, but more space in the housing is needed for this, that is often not available. In addition, cables generally exhibit a higher inductivity than, for example, planar ground connections, which disadvantageously affects the EMI behavior.
Furthermore, a use of CuBe springs for grounding is known (see www.infratron.de; www.zillkon.de).